The present invention relates to an ink jet recording sheet which uses mainly an aqueous ink and particularly to an ink jet recording sheet which is excellent in drying properties and in water resistance of images and further, high in gloss.
Since ink jet recording produces little noise and makes high-speed printing possible, ink jet recording has now become widespread rapidly. Color recording can be performed relatively easily by using two or more ink nozzles, and a variety of color ink jet recording systems have been developed. Recently, use of ink jet printers as a means of obtaining computer hard copies, that has enabled quick and accurate formation of computer-drawn images consisting of graphics and fonts, is attracting attention. Such computer-drawn and ink-jet printed hard copies are not limited to paper sheets, but also transparencies for overhead projectors (hereinafter referred to as "OHP") that are quite commonly used nowadays in presentations. Moreover, a particularly noticeable field of use nowadays of the computer-drawn and ink jet printed hard copy is a color proof in printing industry or a proof output of designs where a photographic quality color image development is required.
As inks for ink jet recording, those which are mainly composed of aqueous solution of a polyhydric alcohol are used from the points of safety, desired recording characteristics and inhibition of clogging. Improvements of these characteristics are still being on the way.
As the recording sheet for ink jet recording, there have been generally used an ordinary non-coated paper or special sheet comprising a support and a porous ink-absorbing layer provided thereon which is called ink jet recording sheet.
However, there are certain serious problems when the conventional ink jet recording sheets are used for a color proof or design proof in which high gloss and quick drying properties are required. That is, when the conventional ink jet recording sheet comprising a support and a porous ink-absorbing layer provided on the support is printed by an ink jet printer, the gloss decreases owing to the light scattering by the porous ink-absorbing layer and such sheet cannot be practically used. Further, when the conventional ink-absorbing layer is used for OHP, the porous ink-absorbing layer causes reduction of the light transmission even when a transparent support is used.
When the surface of the ink-absorbing layer is nonporous, the light transmission can be improved, but since it is inferior in aqueous ink receptivity, the ink remains wet for a long time on the surface of the sheet after the image has been recorded and a long time is required for fixing or drying the recorded images. Furthermore, the known ink jet recording sheets lack water resistance of the images printed thereon and cannot be employed for such use as requiring water resistance.
In order to solve these problems, various recording sheets having a transparent ink-absorbing layer high in ink receptivity have been proposed. For example, there are proposed use of polyvinyl alcohol and polyacrylic acid-based water-soluble polymers in Japanese Patent Kokai (Laid-Open) No. 60-168651, use of hydroxyethyl cellulose in Japanese Patent Kokai (Laid-Open) No. 60-262685, use of a mixture of carboxymethyl cellulose and polyethylene oxide in Japanese Patent Kokai (Laid-Open) No. 61-181679, use of a mixture of a water-soluble cellulose and polyvinyl pyrrolidone in Japanese Patent Kokai (Laid-Open) No. 61-193879, use of a receiving layer formed of an aqueous gelatin solution of a specific pH in Japanese Patent Kokai (Laid-Open) No. 62-263084, and use of a mixture of gelatin and a surfactant in Japanese Patent Kokai (Laid-Open) No. 1-146784.
The recording sheets disclosed in these patent publications are superior in light transmission. However, even these recording sheets cannot satisfactorily attain the quick drying properties of the ink and high gloss of the sheets together and cannot be used for color proofs or design proofs.